How Often Should You Clean Draft Beer Lines? The Calendar Is Not the Answer.
Every 14 days is the published standard, and it is a reasonable floor. It is also an input, not an outcome. A cleaning schedule tells you what was supposed to happen. It does not tell you whether the line came back clean, or what that line cost you in the two weeks before someone got to it.
What the standard actually says
The Brewers Association Draught Beer Quality Manual prescribes routine cleaning every 14 days, using a caustic chemistry followed by an acid treatment and a water rinse. That is a good procedure and a sensible interval.
It prescribes a frequency. It does not prescribe verification. Nothing in the standard tells you how to confirm the cleaning happened, how to confirm it worked, or how one location compares to another. Most operators fill that gap with a clipboard and a signature.
What is actually growing in the line
A 2021 study sampled four retail draft taps at two points about a year apart. It identified 119 bacterial and 18 fungal species as contaminants, dominated by Acetobacter, Fructilactobacillus and Serratia. One organism, Fructilactobacillus lindneri, was overrepresented in the biofilms by roughly 50 percent. The biofilms persisted through cleaning.
Read that last part again. Cleaning happened, and the biofilm was still there.
Worth being straight about what this is and is not. These are spoilage organisms, not pathogens. Dirty lines are a beer quality problem far more than they are a public health problem, and vendors who sell the fear are selling past the actual issue. What these organisms produce is sour, buttery, cidery beer and persistent foam. Guests rarely send that beer back. They order something else, or they stop ordering draft.
What it costs before anyone notices
Foam is beer. It leaves the keg, it goes down the drain, and it never reaches a ticket. That gap between what you poured and what you sold is the whole loss, and it accrues quietly every day the line is degrading.
At Station 7, a Martin City Brewing Company location, unsold poured ounces ran $3,705.80 over seven days. After calibration, the same venue pouring the same volume ran $63.91 over seven days. That is $3,641 recovered in a week, from pour behavior and line condition, not from selling more beer.
The three questions worth asking instead
Did it happen? A signature on a log is a claim. A timestamped drop in flow resistance is a record.
Did it work? A line that pours the same before and after was not cleaned in any way that matters.
What changed? If waste did not move after the cleaning, the problem was never the line. It was pressure, temperature, or the pour.
The practical version
Keep 14 days as the floor. Do not treat it as the ceiling or the goal.
Record the event, not the intention. Timestamp it against system data so it cannot be back-filled.
Measure the line before and after. Temperature, pressure, flow, and poured ounces against POS.
Compare locations. If one venue needs cleaning every 10 days and another holds at 21, you have found draft drift, and the calendar was hiding it.
Clean lines are not the goal. Beer you poured and actually sold is the goal. Cleaning is one of several ways to get there, and it is the only one most operators can currently see.
PourScore™ measures volume, temperature, pressure, and sanitation events on every draft line and reconciles pours against POS sales in real time. See it running on a real venue.
